Apparatus and method for balancing aircraft with robotic arms

ABSTRACT

A hover-capable flying machine such as a drone includes a robotic arm extending from the body, and an instrumentality for balancing the machine in response to disturbances such as those caused by picking up and dropping of the payload by the extended robotic arm. In embodiments, the end of the arm is equipped with a balancing rotor assembly that may provide lift sufficient to counteract the weight of the payload and/or of the arm. In embodiments, the machine&#39;s power pack is shifted in response to the disturbances. The power pack may be moved, for example, on a rail within and/or extending beyond the machine in a direction generally opposite to the extended arm. The power pack may also be built into a bandolier-like device that can be rolled-in and rolled out, thus changing the center of gravity of the machine.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is the national stage entry of PCT InternationalApplication PCT/US17/56216, WIPO publication WO2018/071592; which claimspriority from U.S. provisional patent application Ser. No. 62/407,971,entitled APPARATUS AND METHOD FOR BALANCING AIRCRAFT WITH ROBOTIC ARMSAND PAYLOADS, filed on 13 Oct. 2016. Each of the patent documentsidentified above is hereby incorporated by reference in its entirety asif fully set forth herein, including text, figures, claims, tables, andcomputer program listing appendices (if present), and all other mattertherein.

FIELD

The present description generally relates to stabilization and balancingof aircraft with robotic arms used for lifting, carrying, and/ordropping various payloads. In selected embodiments, the presentdescription relates to drones with robotic arms and other aircraftcapable of hovering.

BACKGROUND

Unmanned Aerial Vehicles (UAVs), also known as Unmanned Aerial Systems(UASs), Unmanned-Aircraft Vehicle Systems (UAVSs), Remotely PilotedAerial Vehicles (RPAVs), Remotely Piloted Aircraft Systems (RPASs), andmore commonly, as drones, are powered aerial vehicles (i.e., aircraft)that do not carry a pilot or human operator on board, can flyautonomously or be piloted remotely, and can carry payloads. Drones arepresently used for intelligence gathering (e.g., through aerialphotography), as missile delivery systems in military and intelligenceoperation, and for recreation by consumers. Drones can be employed forpayload deliveries and pickups, among many other tasks. Drones areparticularly useful for missions that are dangerous, monotonous, orotherwise impractical or unpleasant for a pilot, but can also be morecost-efficient than human-operated aircraft even for more agreeablemissions.

There are generally three modes of drone operation: (1) autonomousoperation by an onboard flight controller; (2) autonomous operation by aremote flight controller via remote control; (3) remote operation by ahuman operator, that is, operation by a human via remote control. It is,of course, possible to have a drone capable of some mixture of two ormore of the modes described above. For example, different modes may beengaged at different times, and/or for different functions or tasks; anddifferent modes may be engaged at the same time to control differentfunctions and capabilities.

Drones are usually multirotor aircrafts. One of the most popular dronedesigns is a quadcopter (or quadroter/quadrotor/quadrone) design—a dronedesign with four equally-spaced, high-speed rotors. Multirotor and otherdrones may be equipped with sensors to get information about theirsurroundings and their states (such as attitude and velocity). Suchsensors may include 3D gyro, accelerometer, magnetometer, pressorsensor, GPS, camera, battery level sensor, radio control receiver, andothers. Multirotor drones are typically controlled through radio remotecontrollers.

Rotors may be powered by electrical motors, for example, brushless DCmotors.

Military and industrial UAVs are often powered by combustion enginesrequiring fuel. Some UAVs use solar power. Most consumer drones,however, operate on batteries. Currently, the most popular source ofenergy in consumer drones appears to be Lithium-Polymer (LiPo)batteries. Nickle Cadmium (NiCad) and Nickle Metal Hydride (NiMH) werefirst used, but Lithium batteries (Lithium Ion or LiPo) are generallysuperior to NiCad batteries because they typically have higher powerdensities, higher energy storage densities, and have longer lives.Lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), lithium polymer,and lithium titanate batteries are also used in drone applications.

Some drones use charging stations to recharge.

Batteries are made of cell(s), from one to several, which may beconnected in series and/or in parallel. If two similar cells areconnected in series (positive to negative), the voltage will double, butcurrent capacity will stay the same. Connecting two similar cells inparallel (positive to positive and negative to negative) doubles currentcapacity, but voltage will stay the same. Thus, it is possible tocombine two or more batteries in parallel to multiply the total energyand current capacity; and it is also possible to combine two or morebatteries in series to multiply the energy and output voltage.

To prolong the flight time, larger batteries are required. However,larger batteries (e.g., with more battery cells) increase the weight ofthe aircraft, requiring more power.

A quadrone (a.k.a. quadrotor) is a particularly popular drone havingfour rotors. Examples of quadrones are illustrated in FIGS. 1A and 1B.

Quadrones may have several body (frame) configurations supporting thefour rotors, examples of which are illustrated in FIGS. I1C.

Another frame configuration is Quad H, an example of which isillustrated in FIG. 1D.

The four rotors of a quadcopter may be made up of two pairs of rotors.One pair of oppositely-located rotors may rotate clockwise. The otherpair of oppositely-located rotors may rotate counterclockwise. Theangular momenta generated by the two sets of rotors cancel out so thatthe quadcopter does not pivot or yaw. This concept is illustrated inFIGS. 1E and 1F.

Other multirotors may have more than two such pairs of rotors, forexample, totaling six, eight, or even more rotors.

Alternatively, two coaxial counter-rotating rotors may be placed one ontop and the other on the bottom.

The so-called X8 (a.k.a. an octocopter or octorotor) configuration issimilar to a quadrotor configuration but has two rotors per arm.Octorotors may have all eight rotors arranged in a disc.

Examples of various quadrotor, hexrotor, and octorotor configurationsare illustrated in FIG. 1G.

As has already been mentioned, another configuration uses two coaxialcounter-rotating rotors instead of one—one rotor on top and anothercounterrotating rotor on the bottom or vice versa. This allows almostdouble the lift force with only 10-20% loss of efficiency because thebottom rotor operates in a wash from the top rotor. This double-rotorassembly is typically used in Hex Y, Hex IV, and Oct X configurations.Examples are illustrated in FIG. 1H1 and FIG. 1H2.

To describe the orientation of an aircraft, three angles are used: roll,pitch, and yaw, as is illustrated in FIGS. 1I and 1J.

The roll angle of an aircraft describes how the aircraft is tilted sideto side. Rolling any multirotor causes it to move sideways.

The pitch angle of an aircraft describes how the aircraft is tiltedforward or backward. Pitching the multirotor causes it to move forwardor backward.

The yaw angle of an aircraft describes its bearing, or, in other words,rotation of the craft as it stays level to the ground.

In a rotorcraft (e.g., a multirotor), lift is produced by the rotors.Total lift is equal to the sum of the lift produced by each of therotors. To increase the altitude of a quadcopter, for example, the RPMof all four rotors may be increased and, to decrease the altitude of thequadcopter, the RPM of all four rotors may be decreased. If the force ofgravity equals the force of the lift produced by the rotors, themultirotor should maintain a constant altitude (assuming its velocityvector has no vertical component).

By adjusting the relative speeds of the motors in just the right ways,keeping in mind that the rotational speed of the motors determines howmuch lift each rotor produces, the flight controller of a multirotor maycause the multirotor to rotate around any of the directional axes (roll,pitch, and yaw), or make the multirotor gain or lose altitude.

Pitch controls whether the quadcopter flies forward or backward. Topitch the front of the quadcopter (nose) down and the rear up, whichresults in a forward moment, the RPM of the rear rotors may beincreased, and/or RPM of the front rotors may be decreased. To pitch aftthe aircraft, the RPM of the front rotors may be increased, and/or theRPM of the rear rotors may be decreased, causing the quadcopter to movebackward.

To roll the quadcopter along the longitudinal axes, the RPM of therotors on one side may be increased and/or RPM of the rotors on theother side may be decreased.

Increasing or decreasing RPM on the opposite rotors increases theangular momentum, causing the quadcopter to yaw.

Flight controller or flight control system (FCS) is an onboard computerthat coordinates all rotors to stabilize the flight of the multirotoraircraft. There are FCSs capable of making 600 or more adjustments persecond.

Aircraft often carry payloads. Airplanes may carry payloads in theirfuselages, and drones typically carry payloads underneath theirfuselages.

Every aircraft generally must carry fuel or batteries (a.k.a. power packor energy bank) that power the aircraft. The fuel may be gasoline or asimilar fuel for internal combustion engines, or kerosene or other fuelfor jet engines. Electric motors have lately been commonly used forpropulsion of drones. Batteries are needed to power such electricmotors. Attaching batteries (or a fuel tank) rigidly to the fuselage ofan aircraft increases the weight and further reduces the aircraft'smaneuverability.

Drones with one or more robotic “arms” adapted for handling varioustasks can be particularly useful. A robotic arm is a mechanical arm ormanipulator that may be programmable and may be operated autonomously bya CPU or by a remote operator. The links of such arm may be connected byjoints, allowing rotational motion and translational (linear)displacement. The links of the manipulator may be considered to form akinematic chain. The terminus of the kinematic chain of the manipulatoris called the end effector. There are different types of robotic arms.

Cartesian robots are used for picking up and placing objects, assemblyoperations, and similar tasks. Arms in such robots may have threeprismatic joints, whose axes are coincident with a Cartesiancoordinator.

Cylindrical robots are used for assembly operations, handling of machinetools, spot welding, and handling in die-casting machines. Cylindricalrobot arm axes form a cylindrical coordinate system, as is illustratedin FIG. 1K.

Spherical robots are used for handling machine tools, spot welding, andother tasks. Such robots have two rotary joints and one prismatic joint,i.e., two rotary axes and one linear axis. Spherical robots have armsforming a spherical coordinate system.

Selective Compliance Assembly Robot Arm (also known as SelectiveCompliance Articulated Robot Arm or SCARA) robots are used for pickingup and placing objects, assembly operations, and handling of machinetools. Such robots feature two parallel rotary joints to providecompliance in a plane; this notion is illustrated in FIG. 1L.

Articulated robots are used for assembly operations, die-casting,fettling machines, gas welding, arc welding, and spray painting, amongother applications. An articulated robotic arm has at least three rotaryjoints.

A parallel robot is a robot whose multiple arms support a platform andhave prismatic or rotary joints.

In an anthropomorphic robot, a robotic hand resembles a human hand,i.e., a device with independently-operable fingers/thumb.

One type of tasks performed by drones with robotic arms is using thearms for picking up, carrying, and dropping off objects. Drones designedfor such tasks may be hovering drones. The drop-offs and pickups may beto/from places that are not accessible vertically, that is, places notaccessible from directly above with sufficient room for the drone tooperate. Typically, one arm is positioned directly underneath the centerof the drone, so that the arm itself and, especially, the payload, doesnot shift the center of gravity and tilt the drone. In someapplications, two arms may be desirable for lifting, caring, anddelivering certain types of payloads. When one or two robotic armsextend horizontally from a drone (and even more so when these arms liftand carry payloads), the center of gravity moves and may cause theaircraft to lose its balance. Another type of the tasks is when forcewith a vertical component needs to be applied to an object external tothe drone. For example, an attempt to lift a payload by a robotic arm(s)in front of the drone may tilt the front of the drone down, which isundesirable. Performing such tasks by a robotic arm may unbalance thedrone. Pitching the front of the drone down would result in a forwardmotion of the drone, as the lift of the drone's rotor(s) acquires ahorizontal component. Moreover, the vertical component of the lift woulddiminish (as part of the energy is converted to horizontal motion), andthe drone would lose altitude.

The problem of maintaining balance and attitude in the course ofperforming the balance-altering tasks is also present in hover-capableflying machines that are operated by human onboard pilots.

Therefore, it is desirable to provide improved techniques and designsfor balancing flying machines.

SUMMARY

A need exists in the art for improved methods for maintaining balance inflying machines while lifting, carrying, or manipulating payloads, andin other similar circumstances, and for flying machines with improvedbalancing capabilities. A further need in the art exists for improvedmethods for maintaining balance in hover-capable flying machines (suchas helicopters and drones), and for hover-capable flying machines withimproved balancing capabilities. Yet another need in the art exists forimproved methods for maintaining/controlling balance and attitude inhover-capable flying machines with robotic arms, and for hover-capableflying machines with robotic arms and improved balancing capabilities.Still another need in the art exists for improving techniques ofcarrying fuel or electrical batteries in a flying machine, and forflying machines with dynamic distribution of weight, particularly theweight of fuel or electrical batteries powering the flying machine.

Embodiments disclosed in this document are directed to apparatus andmethods that satisfy one or more of these and/or other needs.

In accordance with one embodiment of the present invention, a flyingmachine capable of hovering includes a body (frame); at least onerobotic arm extending from the body, the robotic arm terminating in anend effector, one or more main rotor assemblies; and a balancing rotorassembly located substantially above the end effector to provide liftcompensating for weight of the payload carried by the end effector.

In accordance with another embodiment of the present invention, a flyingmachine capable of hovering includes a body; at least one robotic armextending from the body, the robotic arm terminating in an end effector,one or more main rotor assemblies; a power pack; and means for movingthe power pack in relation to the body and balancing the hover-capablemachine in response to changes in payload carried by the end effector.

In accordance with another embodiment of the present invention, a flyingmachine capable of hovering includes a body, a power pack external tothe body and dynamically positioned with respect to the body to helpmaintain the balance of the flying machine. The power pack may be abattery or a plurality of battery cells connected in parallel orsequentially.

In accordance with another embodiment of the present invention, a flyingmachine capable of hovering includes a body, a power pack external tothe body and dynamically positioned with respect to the body to helpmaintain the balance of the aircraft.

In accordance with another embodiment, a flying machine capable ofhovering includes a body; at least one energy bank, said at least oneenergy bank being one of a battery pack and a fuel tank; a robotic armextending from the body, the robotic arm comprising a plurality oflinks, one or more joints, and an effector, the links of the pluralityof links being connected by the one or more joints, the robotic armending in the effector; one or more main rotor assemblies supported bythe body and operatively connected to said at least one energy bank; alanding gear, and a balancing rotor assembly located substantially abovethe effector to provide lift compensating for weight of payload carriedby the effector.

In accordance with another embodiment, a flying machine capable ofhovering includes a body; at least one robotic arm extending from thebody, said at least one robotic arm comprising an effector, said atleast one robotic arm ending in the effector; one or more main rotorassemblies; an extendable tail positioned on the opposite side of thebody with respect to said at least one robotic arm; a power pack storedsubstantially at the end of the extendable tail; a motor for moving thepower pack in relation to the body by regulating length of theextendable tail; and a controller linked to the motor, wherein thecontroller is configured to maintain the center of mass of the flyingmachine in response to changes in payload carried by the effector. Inaspects, the extendable tail is a telescopic tail. In aspects, theextendable tail is an accordion tail.

In accordance with another embodiment, a flying machine capable ofhovering includes a body; at least one robotic arm extending from thebody, said at least one robotic arm comprising an end effector, said atleast one robotic arm terminating in the end effector, one or more mainrotor assemblies; a flexible tail positioned on the opposite side of thebody with respect to said at least one robotic arm; a plurality oflinked battery cells spaced parallel to each other throughout the tail;a motor for regulating length of the tail in relation to the body byrolling up and unrolling out the tail; and a controller linked to themotor, wherein the controller is configured to maintain the center ofmass of the flying machine in response to changes in payload carried bythe end effector.

These and other features and aspects of the present invention orinventions will be better understood with reference to the followingdescription, drawings, and appended claims.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A through 1L illustrate various hover-capable flying machines,their configurations, and associated concepts;

FIG. 2A is a side view illustrating selected components of ahover-capable flying machine with a robotic arm and using a balancingrotor assembly mounted on the robotic arm;

FIG. 2B is a perspective view illustrating selected components of thehover-capable flying machine of FIG. 2A;

FIG. 3A is a side view illustrating selected components of ahover-capable flying machine with a robotic arm, balanced by shifting anenergy bank on a telescoping boom, with the telescoping boom in acontracted or shortened state;

FIG. 3B is a perspective view illustrating selected components of thehover-capable flying machine of FIG. 3A with the telescoping boom in anextended state;

FIG. 4 is a side view illustrating selected components of ahover-capable flying machine with a robotic arm, balanced by shifting anenergy bank on an accordion- or scissor-type boom;

FIG. 5 is a side view illustrating selected components of ahover-capable flying machine with a robotic arm, balanced by moving anenergy bank along a fixed boom;

FIG. 6A is a side view illustrating a power bandolier tail made withcylindrical cells, in a fully extended configuration;

FIG. 6B is a side view illustrating a power bandolier tail made withquadrangular cells, in a fully extended configuration;

FIG. 6C is a side view illustrating the power bandolier tail of FIG. 6Amade with cylindrical cells, in a partially rolled-in configuration;

FIG. 6D is a side view illustrating the power bandolier tail of FIG. 6Amade with cylindrical cells, in a completely rolled-in configuration;

FIG. 6E is a side view illustrating the power bandolier tail of FIG. 6Bmade with quadrangular cells, in a partially rolled-in configuration;

FIG. 6F is a side view illustrating the power bandolier tail of FIG. 6Bmade with quadrangular cells, in a completely rolled-in configuration;

FIG. 7A is a side view illustrating selected components of ahover-capable flying machine with a robotic arm and a cylindrical powercell bandolier tail in an extended configuration;

FIG. 7B is a perspective view illustrating selected components of thehover-capable flying machine of FIG. 7A;

FIG. 7C is a side view illustrating selected components of thehover-capable flying machine of FIGS. 7A and 7B where the power cellbandolier tail is in a partially rolled-in configuration;

FIG. 8A is a side view illustrating selected components of ahover-capable flying machine with a robotic arm and a quadrangular powercell bandolier tail in an extended configuration; and

FIG. 8B is a side view illustrating selected components of thehover-capable flying machine of FIG. 8A where the power cell bandoliertail is in a partially rolled-in configuration.

DETAILED DESCRIPTION

The aspects, features, and advantages of the present invention will beappreciated when considered with reference to the following descriptionof exemplary embodiments, and the accompanying figures.

In this document, the words “embodiment,” “variant,” “example,” andsimilar expressions refer to a particular apparatus, process, or articleof manufacture, and not necessarily to the same apparatus, process, orarticle of manufacture. Thus, “one embodiment” (or a similar expression)used in one place or context can refer to a particular apparatus,process, or article of manufacture; the same or a similar expression ina different place can refer to a different apparatus, process, orarticle of manufacture. The expression “alternative embodiment” andsimilar expressions and phrases are used to indicate one of a number ofdifferent possible embodiments. The number of possible embodiments isnot necessarily limited to two or any other quantity. Characterizationof an item as “exemplary” means that the item is used as an example.Such characterization of an embodiment does not necessarily mean thatthe embodiment is a preferred embodiment; the embodiment may but neednot be a currently preferred embodiment. The embodiments are describedfor illustration purposes and are not necessarily strictly limiting.

The words “couple,” “connect,” and similar expressions with theirinflectional morphemes do not necessarily require an immediate or directconnection (although they do include direct/immediate connections), butmay also include connections through mediate elements within theirmeaning, unless otherwise specified or inherently required.

The term “flying machine” includes within its meaning (1) drones withautonomous operation by an onboard flight controller; (2) drones withautonomous operation by a remote flight controller via remote control;(3) drones remotely operated by a human operator via remote control; (4)flying apparatus operated by an onboard human pilot; and (5) flyingapparatus capable of some mixture of two or more of the operationalmodes described above. A flying machine thus may but need not be adrone, and may but need not be hover-capable. A “hover capable flyingmachine,” however, needs to be capable of hovering.

An “arm” or a “robotic arm” may be a manipulator arm; it may bearticulated (that is, with one or more joints/pivots and two or moremembers) or non-articulated; an arm may be attached to the flyingmachine rigidly or non-rigidly, that is, via a rotary, universal, orother joint/pivot.

“Power source” and “energy bank” are used interchangeably to signify thesource of energy for operation of a flying machine, such as energy forpowering main rotor(s) of the machine.

Other and further definitions and clarifications of definitions may befound throughout this document.

Reference will now be made in detail to several embodiments andaccompanying drawings. Same reference numerals are used in the drawingsand the description to refer to the same apparatus elements and methodsteps. The drawings are in a simplified form, not necessarily to scale,and omit apparatus elements and method steps that can be added to thedescribed apparatus and methods, while including certain optionalelements and steps.

FIGS. 2A and 2B illustrate selected components of a hover-capable flyingmachine (“HCFM”) 100. The HCFM 100 includes main rotor assemblies 105, abody 110, and at least one power bank (not specifically illustrated inthese Figures). The main rotor assemblies 105 here include quadcounter-rotating coaxial rotors that may entirely or substantiallyentirely cancel each other's angular momentum or torque. In otherembodiments, one or more than two pairs of coplanar counter-rotatingrotors may be used, configured so that in each pair of thecounter-rotating coplanar rotors the angular momentum or torque of anindividual rotor of the pair entirely or substantially entirely cancelsthe angular momentum or torque of the other rotor of the pair. As shownin the Figures, engines/motors 107 power their respective rotorassemblies 105; in other embodiments, one or more engine/motors insidethe body 110 activate the rotor assemblies 105, for example, throughgears, chains, shafts, and similar power transmission components. Themain rotor assemblies 105 may be tilting, either separately or together,so that the HCFM 100 may hover and move horizontally, like a helicopter.In embodiments, a boom with a tail rotor with a horizontal axis ofrotation is included, and the main rotor assemblies 107 in suchembodiments need not (but still may) include counter-rotating rotors. Inembodiments, each main rotor assembly 107 includes counter-rotatingcoaxial rotors; examples of such rotor assemblies are illustrated inFIGS. 1H1 and 1H2. In embodiments, a single main rotor assembly is usedin conjunction with a boom and a tail rotor, as in a typical helicopterwith a single main rotor. Other HCFM arrangements may also be used.

In embodiments, the main rotor assemblies 105 and/or any other rotorassembly described in this document and/or shown in the Figures is aducted fan assembly. In embodiments, some rotor assemblies arereversible; for example, an assembly's thrust direction may bereversible by rotating the assembly, reversing the polarity of theelectrical energy applied, or changing gears in a transmission between amotor and one or more of the assembly's rotors.

The HCFM 100 also includes an articulated arm 120. As shown in the FIGS.2A and 2B, the articulated arm 120 is attached to a platform 128 with ajoint 121 and includes intermediate members 122 and 123, an end member(a.k.a. “end effector”) 124, and joints 125 and 126 that allowarticulation. The platform 128 is attached to the body 110 with arotating shaft 129, so that the articulated arm 120 may be extendedhorizontally in any direction. The end member 124 may include at its end(away from the joint 126) a claw, a hook, a grasp, or another tool 127.The tool may be controllable, for example, allowing grasping andreleasing of payloads. Other types of arms, articulated andnon-articulated, may also be employed. In examples, the arm may be, forexample, a Cartesian robotic arm, a cylindrical robotic arm, a sphericalrobotic arm, a selective compliance assembly robotic arm (SCARA), anarticulated robotic arm, a parallel robotic arm, or an anthropomorphicrobotic arm. The arm and any of its joints and/or other components maybe operated or moved using, for example, electrical and/or hydraulicactivation under control of a controller (e.g., the FCS of the HCFM 100or another controller) and/or a pilot.

Above the tool 127 at the end of the arm 120 is a balancing rotorassembly 140. The axis of the balancing rotor assembly 140 is generallyin a vertical direction, so that the lift generated by the balancingrotor assembly 140 may counterbalance the tool 127 with or without apayload held by the tool 127 (and possibly also or insteadcounterbalance some of the weight of the other portions of the arm 120).In embodiments, the balancing rotor assembly 140 includes coaxialcounter-rotating rotors. In embodiments, the balancing rotor assembly140 is or includes multiple (2, 3, 4, or more) rotors used forbalancing. In embodiments, the balancing rotor assembly 140 is identicalor similar (e.g., in dimensions, aerodynamics, available power, and/orlift-generation ability) to one of the main rotor assemblies 105 or oneof the other rotor assemblies of the HCFM 100. In embodiments, the power(e.g., electrical power) for the balancing assembly 140 is provided froma power source located in the body 110 or another location of the HCFM100. In embodiments, a common power source energizes the balancing rotorassembly 140 and the main rotor assemblies 105, and/or other rotorassemblies. In embodiments, the common power source, such as anelectrochemical rechargeable or primary battery/cell, energizes all therotors and propeller (if present) assemblies of the HCFM 100.

In embodiments, a controller (e.g., the FCS of the HCFM 100) is coupledto the at least one energy bank and automatically varies the powerprovided to the balancing rotor assembly 140 to reduce or minimize theforces resulting from pickup or release of a payloads by the tool 127.Thus, if the tool 127 is a claw or another attachment/graspingmechanism, the controller may simultaneously or substantiallysimultaneously release or lower to a surface the payload held by thetool 127 and reduce the power to the balancing rotor assembly 140; aftergrasping a payload, the controller may simultaneously or substantiallysimultaneously increase the power to the balancing rotor assembly 140,and the main rotor assemblies 105 to cause the HCFM 100 to ascendwithout tipping over because of the weight of the payload grasped/heldby the tool 127 at the end of the extended arm 120. Thus, the controllermay simultaneously or substantially simultaneously lower the payloadheld by the tool 127 by operating the arm 120 (such as lowering the endof the arm with the tool 127 with respect to the body 110) and reducethe power to the balancing rotor assembly 140; and simultaneously orsubstantially simultaneously raise the payload held by the tool 127 byoperating the arm 120 (such as raising the end of the arm with the tool127 and the payload with respect to the body 110) and increase the powerto the balancing rotor assembly 140. In this way, the forces on the body110 caused by the operation of the arm 120 are reduced or eveneliminated.

In coordinating the actions of the arm 120 and the power driving thebalancing rotor assembly 140, the controller may receive sensor readingsthat indicate the attitude (or changes in the attitude) of the body 110,and/or the force/torque between the arm 120 and the platform 128, and/orthe force/torque between the members of the arm 120. The controller mayreceive and use (for balancing, in a feedback manner) input from anysensors that indicate the attitude or changes in attitude of the HCFM100 and/or the balance between the load carried by the tool 127 and thelift generated by the balancing rotor assembly 140. If the HCFM 100 isoperated by a human (such as an onboard or remote pilot), the pilot mayprovide the coordinated action. The human pilot may rely on his or hersenses in determining the attitude if the HCFM and/or on a screendisplay showing images received by one or more HCFM onboard or externalcameras.

While the above examples focus on the initial pickup or drop-off of thepayload, the same general approach with necessary variations may beemployed when the arm 120 is extended away from or brought closer to thebody 110, with or without a payload. The balancing rotor assembly 140may also be operated in flight to improve flight characteristics of theHCFM 100. In embodiments, the arm 120 may be operated so that the axisof the balancing rotor assembly 140 has a horizontal component, forexample, the axis may be completely or almost completely horizontal, andthe balancing rotor assembly may thus be used to provide horizontalpropulsion for the HCFM 100.

The HCFM 100 may be a quadrone with four main rotor assemblies, whereineach pair of two oppositely disposed rotors has the same angularvelocity, one pair of rotors rotating clockwise and the other pairrotating counterclockwise. As noted above, other numbers of rotors maybe used, including even numbers of main rotor assemblies with pairedrotors, and odd numbers of main rotor assemblies.

In embodiments, the main rotor assemblies 105 of the HCFM 100 include atleast one pair of coaxial counter-rotating rotors configured to cancelangular momentum generated by each rotor of the at least one pair ofcoaxial counter-rotating rotors. In embodiments, the main rotorassemblies 105 of the HCFM 100 include at least one pair of coaxialcounter-rotating rotors configured to cancel angular momentum generatedby each rotor of the at least one pair of coaxial counter-rotatingrotors. In embodiments, the main rotor assemblies of the HCFM 100include three pairs of coaxial counter-rotating rotors. In embodiments,the main rotor assemblies of the HCFM 100 are arranged in otherconfigurations described in this document, such as Quad I, Quad X, HexI, Hex V, Hex Y, Hex IY, Oct X, Oct I, and Oct V configuration.

FIGS. 3A and 3B illustrate selected components of an HCFM 300 that isbalanced in a different way. The HCFM 300 is similar to the HCFM 100described above. It includes main rotor assemblies 305 similar oridentical to the main rotor assemblies 105; and a body 310, similar oridentical to the body 110. Thus, each of the main rotor assemblies 305may include dual counter-rotating coaxial rotors that entirely orsubstantially entirely cancel each other's angular momentum or torque,or one or more pairs of coplanar counter-rotating rotors configured sothat in each pair the counter-rotating coplanar rotors entirely orsubstantially entirely cancel each other's angular momentum or torque.As shown in the Figures, engines/motors 307 power their respective rotorassemblies 305; in embodiments, one or more engine/motors inside thebody 310 activate the rotor assemblies 305, for example, through gears,chains, shafts, and similar power transmission components. The mainrotor assemblies 305 may be tilting, so that the HCFM 300 may hover andmove horizontally, as a helicopter. In embodiments, the main boom with atail rotor with a horizontal axis of rotation is included, and the mainrotor assemblies 305 or assemblies in such embodiments need not (butstill may) include counter-rotating rotors. In other embodiments,multiple counter-rotating main rotors with different axes of rotationmay be present. In still other embodiments, multiple assemblies ofcounter-rotating rotors may be present. Other HCFM arrangements may alsobe used.

The HCFM 300 also includes an articulated arm 320, which is similar oridentical to the articulated arm 120. As shown in FIGS. 3A and 3B, thearticulated arm 320 is attached to a platform 328 with a joint 321 andincludes intermediate members 322 and 323, an end member or end effector324, and joints 325 and 326 that allow articulation. The platform 328 isattached to the body 310 with a rotating shaft 329, so that thearticulated arm 320 may be extended horizontally in any direction. Theend member 324 may include at its end (away from the joint 326) a claw,a hook, a grasp, or another tool 327. The tool may be controllable, forexample, allowing grasping and releasing of payloads. Other types ofarms, articulated and non-articulated, may also be employed. Inexamples, the arm may be, for example, a Cartesian robotic arm, acylindrical robotic arm, a spherical robotic arm, a selective complianceassembly robotic arm (SCARA), an articulated robotic arm, a parallelrobotic arm, or an anthropomorphic robotic arm. The arm and any of itsjoints and/or other components may be operated or moved using, forexample, electrical and/or hydraulic activation under control of acontroller (e.g., the FCS of the HCFM 300 or another controller) and/ora pilot.

Note that here, unlike in the HCFM 100, there is no balancing rotorassembly above the tool 327. The balancing is achieved by shifting anenergy bank 350 (power source that energizes the HCFM 300) relative tothe body 310. As shown in FIGS. 3A and 3B, a telescoping power boom 345is attached to the platform 328 substantially opposite the attachment ofthe arm 320, and the energy bank 350 is attached at the opposite end ofthe telescoping power boom 345. The energy bank 350 may be, for example,one or more batteries or fuel cells or fuel tanks.

FIG. 3A illustrates the HCFM 300 with the telescoping power boom 345 ina shortened/contracted/pulled-in state. FIG. 3B illustrates the HCFM 300with the telescoping power boom 345 in an extended state. Thetelescoping power boom 345 is made of a number of tubular sections of aprogressively smaller diameter so that they fit inside each other in anesting arrangement. Telescoping power boom 345 can be extended andcontracted using a motor controlled by the FCS or another controller ofthe HCFM 300 to move the energy bank away from the body 310 and closerto the body 310, respectively. The FCS controls the motor to compensatefor the changes such as those resulting from extending the arm 320,picking up payloads, and dropping off payloads, for example, keeping thecenter of gravity of the HCFM 300 substantially the same with respect tothe body of the HCFM 300. The length of the power boom 345 may also bevaried by the controller through, for example, a hydraulic cylinderactivator.

FIG. 4 illustrates selected components of an HCFM 400 that is similar tothe HCFM 300 discussed above. Here, however, a power boom 445 thatcarries an energy bank 450 is an accordion-type or scissor-type extenderdevice that can be extended and contracted using a motor controlled bythe FCS or another controller of the HCFM 400 to move the energy bank450 away from the body 410 and closer to the body 410, respectively. TheFCS controls the motor to compensate for the changes such as thoseresulting from extending the arm 420, picking up payloads, and droppingoff payloads, for example, keeping the center of gravity of the HCFM 400substantially the same with respect to the body of the HCFM 400. Thelength of the power boom 445 may also be varied by the controllerthrough, for example, a hydraulic cylinder activator.

FIG. 5 illustrates selected components of an HCFM 500 that is also verysimilar to the HCFM 300 discussed above. Here, however, a power boom 545is of a fixed length. An energy bank 550 can be moved along the powerboom 545 by a small motor or servomechanism controlled by a controller;for example, the small motor can cause the energy bank 550 to move backand forth, as needed, along one, two, or any number of parallel rails.

In the HCFMs 300, 400, and 500, when a payload object needs to bereleased by the tool at the end of the robotic arm, the releasing actionmay be coordinated by the controller with the movement of the energybank towards the center of gravity of the HCFM; and when the payload islifted by the tool, the lifting action may be coordinated by thecontroller with the movement of the energy bank away from the center ofgravity of the HCFM. Similarly, when the robotic arm is extended (withor without a payload) or pulled-in (again, with or without a payload)the extension or pulling-in action may be coordinated with the movementof the energy bank away from or towards the center of gravity of theHCFM, as needed for balancing of the HCFM. Thus, the controller (FCS oranother controller) controls the movement of the power bank tocompensate for the changes such as those resulting from extending therobotic arm, picking up payloads, and dropping off payloads, forexample, keeping the center of gravity of the HCFM (including thepayload) substantially the same with respect to the body of the HCFM.

In other embodiments, cells (e.g., electrochemical cells/batteries) ofan energy bank are held by a belt- or bandolier-like device acting as aflexible “tail” of the aircraft. In such a “bandolier” device, a numberof energy cells are held flexibly, similarly to the way cartridges areheld in a real cartridge bandolier; the cells are arranged lengthwise inthe bandolier device, and the bandolier device with the cells can becurled-in (rolled-in) or curled-out (rolled-out), so that its center ofgravity is varied in a controlled manner. We may refer to such a deviceas a “cell bandolier” or “power bandolier.” Examples of such powerbandoliers are illustrated as follows: (1) FIG. 6A illustrates a powerbandolier made of cylindrical cells, in its elongated/extended (notrolled-in) configuration; (2) FIG. 6B illustrates a power bandolier madeof quadrangular cells, in its elongated/extended (not rolled-in)configuration; (3) FIG. 6C illustrates the power bandolier of FIG. 6Amade of cylindrical cells, in a partially rolled-in configuration; (4)FIG. 6D illustrates the power bandolier of FIG. 6A made of cylindricalcells, in a completely rolled-in configuration; (5) FIG. 6E illustratesthe power bandolier of FIG. 6B made of quadrangular cells, in apartially rolled-in configuration; and (6) FIG. 6F illustrates the powerbandolier of FIG. 6B made of quadrangular cells, in a completelyrolled-in configuration.

An example of a drone 700 with such a cylindrical cell bandolier 750 isillustrated in FIGS. 7A (side view, power cell bandolier extended), 7B(perspective view, power cell bandolier extended), and 7C (side view,power cell bandolier partially rolled-in). This embodiment is similar tothe HCFM 300/400/500, with the exception of the weight-shiftingmechanism. Here, the weight shifting mechanism is the power cellbandolier 750 with cylindrical power cells.

An example of a drone 800 with a quadrangular cell bandolier 850 isillustrated in FIGS. 8A (side view, power cell bandolier extended) and8B (side view, power cell bandolier partially rolled-in). Thisembodiment is also similar to the HCFM 300/400/500, with the exceptionof the weight-shifting mechanism. Here, the weight shifting mechanism isthe power cell bandolier 850 with quadrangular power cells.

It should be noted that, although FIGS. 6-8 illustrate cylindrical andquadrangular (square) power cells, cells of other geometries may also beused in the power bandolier, indeed, cells of a general rectangularcross-section are expressly contemplated.

In the HCFMs 700 and 800, a small motor or servomechanism is controlledby the HCFM's FCS or another controller, to roll and unroll the cells ofthe bandolier 750/850. The unrolling takes place in the generaldirection opposite to the direction of extension of the robotic arm ofthe HCFM. In a “dragonfly design,” for example, the arm may be attachedto the “front” of the HCFM body, while the bandolier is unrolled awayfrom the HCFM body towards the “rear” of the HCFM body, tocounterbalance the payload weight and the weight of the arm.

In embodiments, an HCFM has multiple robotic arms. One or more or all ofthe arms may be equipped with balancing rotor assemblies.

In embodiments, an HCFM has multiple weight shifting instrumentalitiessuch as one or more controllable power cell bandoliers and/or one ormore power sources movable on sets of one or more rails and/or scissorextenders and/or telescopic arrangements, extending in the same ordifferent directions.

In embodiments, the main rotor assembly and/or any other rotor assembly(e.g., balancing rotor assembly) includes a reaction engine, such as arocket engine, turbofan, or a jet. Obviously, here the “rotor” in theterm “rotor assembly” should not be taken as literally descriptive butinstead signifying a device for creating thrust.

In embodiments, the balancing rotor assembly (or multiple assemblies)and/or weight shifting instrumentalities are also used by the controllerto compensate for other forces acting on the HCFM, such as wind,turbulence, and collision/impact forces.

Although method steps may be described serially in this document,certain steps may be performed by same and/or separate elements inconjunction or in parallel, asynchronously or synchronously, in apipelined manner, or otherwise. There is no particular requirement thatthe steps be performed in the same order in which this description liststhem or the Figures show them, except where a specific order isinherently required, explicitly indicated, or is otherwise made clearfrom the context. Furthermore, not every illustrated step may berequired in every embodiment in accordance with the concepts describedin this document, while some steps that have not been specificallyillustrated may be desirable or necessary in some embodiments inaccordance with the concepts. It should be noted, however, that specificembodiments/variants/examples use the particular order(s) in which thesteps and decisions (if applicable) are shown and/or described.

The features described throughout this document may be presentindividually, or in any combination or permutation, except where thepresence or absence of specific elements/limitations is inherentlyrequired, explicitly indicated, or otherwise made clear from thecontext.

Although this document describes in detail the inventive apparatus andmethods for balancing flying machines with reference to particularembodiments, it was done for illustration purposes, and it is to beunderstood that these embodiments are merely illustrative of theprinciples and applications of the present invention(s). It is,therefore, to be understood that numerous modifications may be made tothe illustrative embodiments and that other arrangements may be devisedwithout departing from the spirit and scope of the present invention asdefined by the appended claims. Neither the specific embodiments of theinvention or inventions as a whole, nor those of its/their featuresnecessarily limit the general principles underlying the invention(s).The specific features described herein may be used in some embodiments,but not in others, without departure from the spirit and scope of theinvention as set forth herein. Various physical arrangements ofcomponents and various step sequences also fall within the intendedscope of the invention. Many additional modifications are intended inthe foregoing disclosure, and it will be appreciated by those ofordinary skill in the art that in some instances some features of theinvention will be employed in the absence of a corresponding use ofother features. The illustrative examples, therefore, do not necessarilydefine the metes and bounds and the legal protection afforded theinvention or inventions, which are only defined by the claims.

INDUSTRIAL APPLICABILITY

The present invention enjoys wide industrial applicability including,but not limited to, designing and operating aircraft capable ofhovering.

I claim:
 1. A flying machine capable of hovering, the flying machinecomprising: a body; at least one energy bank, wherein said at least oneenergy bank comprises at least one of a battery pack and a fuel tank; arobotic arm extending from the body, the robotic arm comprising aplurality of links, one or more joints, and an effector, wherein thelinks of the plurality of links and the effector are connected by theone or more joints, and the robotic arm ends in the effector; one ormore main rotor assemblies attached to the body and operativelyconnected to said at least one energy bank; a landing gear; and abalancing rotor assembly attached to the robotic arm substantially abovethe effector to provide lift compensating for weight of payload carriedby the effector.
 2. The flying machine of claim 1 wherein: the roboticarm is one of a Cartesian robotic arm, a cylindrical robotic arm, aspherical robotic arm, a selective compliance assembly robotic arm(SCARA), an articulated robotic arm, a parallel robotic arm, oranthropomorphic robotic arm; and the robotic arm is operated by one ofan onboard pilot, an onboard controller, and a remote operator.
 3. Theflying machine of claim 1, wherein the balancing rotor assemblycomprises at least one pair of coaxial counter-rotating rotorsconfigured to cancel angular momentum generated by each of said coaxialcounter-rotating rotors.
 4. The flying machine of claim 1, wherein thebalancing rotor assembly comprises at least one pair of coplanarcounter-rotating rotors configured to cancel angular momentum generatedby each of said coplanar counter-rotating rotors.
 5. The flying machineof claim 1, wherein the balancing rotor assembly comprises a quadrotor.6. The flying machine of claim 1, wherein the flying machine isUnmanned-Aircraft Vehicle System (UAVS), the UAVS further comprising: areceiver; and a flight control system (FCS) linked to the at least oneenergy bank, the receiver, and said one or more main rotor assemblies.7. The flying machine of claim 6, wherein said one or more main rotorassemblies comprise a pair of counter-rotating main rotors configured tocancel angular momentum generated by each rotor of the pair ofcounter-rotating main rotors.
 8. The flying machine of claim 6, whereinthe flying machine is a quadrone, the one or more main rotor assembliescomprise four rotors arranged in two rotor pairs, each of said rotorpairs comprising two oppositely disposed rotors rotating in oppositedirections with the same angular velocity.
 9. The flying machine ofclaim 6, wherein said one or more main rotor assemblies comprise atleast one pair of coaxial counter-rotating rotors configured to cancelangular momentum generated by each rotor of the at least one pair ofcoaxial counter-rotating rotors.
 10. The flying machine of claim 6,wherein said one or more main rotor assemblies comprise three pairs ofcoaxial counter-rotating rotors.
 11. The flying machine of claim 6wherein said one or more main rotor assemblies are arranged in aconfiguration selected from the group consisting of Quad I, Quad X, HexI, Hex V, Hex Y, Hex IY, Oct X, Oct I, and Oct V.
 12. A dronecomprising: a frame; at least one battery pack; a controller attached tothe frame and electrically connected to the at least one battery pack;at least one main rotor assembly attached to the frame and electricallycoupled to said at least one battery pack; a radio receiver attached tothe frame and coupled to the controller; at least one gyroscope attachedto the frame and coupled to the controller; at least one accelerometerattached to the frame and coupled to the controller; a GPS receiverattached to the frame and coupled to the controller; a robotic armattached to the frame, the robotic arm comprising a plurality of links,at least one joint, and an effector, wherein the links of the pluralityof links and the effector are connected by the at least one joint andthe robotic arm ends in the effector; a landing gear; and a balancingrotor assembly attached to the robotic arm above the effector to providelift compensating for weight of payload carried by the effector.
 13. Thedrone of claim 12, wherein the drone is a quadrotor.
 14. The drone ofclaim 12, wherein the frame is one of X, H or Y type.
 15. The drone ofclaim 12, wherein said at least one battery pack comprises a pluralityof battery cells.
 16. The drone of claim 15, wherein at least some ofthe plurality of battery cells are connected in parallel.
 17. The droneof claim 15, wherein at least some of the plurality of battery cells areconnected in series.
 18. The drone of claim 12, wherein said at leastone main rotor assembly comprises a first rotor and a second rotor,wherein the first rotor and the second rotor are coaxialcounter-rotating rotors configured so that the first rotor cancelsangular momentum generated by the second rotor and the second rotorcancels angular momentum generated by the first rotor.
 19. The drone ofclaim 12, wherein said at least one main rotor assembly comprises threepairs of coaxial counter-rotating rotors.
 20. The drone of claim 12,wherein said at least one main rotor assembly comprises a plurality ofmain rotor assemblies arranged in a configuration selected from thegroup consisting of Quad I, Quad X, Hex I, Hex V, Hex Y, Hex IY, Oct X,Oct I, and Oct V configurations.
 21. The drone of claim 12, wherein thebalancing rotor assembly comprises at least one pair of coaxialcounter-rotating rotors configured to cancel angular momentum generatedby each of said coaxial counter-rotating rotors.
 22. The drone of claim12, further comprising a device selected from the group consisting of amagnetometer and a battery level sensor, wherein the device is attachedto the frame and coupled to the controller.
 23. The drone of claim 12,further comprising a video camera.
 24. A system comprising the drone ofclaim 20, and a radio remote controller, wherein the radio remotecontroller can remotely operate the robotic arm.
 25. A drone comprising:a frame, at least one battery pack, at least one main rotor assemblysupported by the frame and electrically coupled to said at least onebattery pack, a controller attached to the frame and electricallycoupled to said at least one main rotor assembly and said at least onebattery pack, a radio receiver attached to the frame and coupled to thecontroller, at least one gyroscope attached to the frame and coupled tothe controller, at least one accelerometer attached to the frame andcoupled to the controller, a GPS receiver attached to the frame andcoupled to the controller, a landing gear, and a robotic arm operativelyconnected to the frame; wherein the robotic arm comprises an effector, aplurality of links connected by at least one joint and ending in theeffector and a balancing rotor assembly located substantially above theeffector and configured to provide lift compensating for weight ofpayload carried by the effector.
 26. A method of balancing a dronecomprising a body, a robotic arm extending from the body and having aplurality of links connected by at least one joint and ending in aneffector, and a balancing rotor assembly attached to the robotic armabove the effector, the method comprising the steps of: monitoringattitude of the body of the drone; and changing power supplied to thebalancing rotor assembly in response to shifting of the attitude tochange the lift produced by the balancing rotor assembly and therebybalance the drone by increasing the power supplied to the balancingrotor assembly in response to pickup of a payload by the effector, andreducing the power supplied to the balancing rotor assembly in responseto releasing or lowering onto a surface the payload carried by theeffector.
 27. A method of balancing a payload carried by a robotic armhaving a plurality of links connected by at least one joint and endingin an effector and a balancing rotor assembly attached to the roboticarm substantially above the effector, wherein the robotic arm isattached to a drone, the method comprising the steps of: monitoring anangle of pitch of the drone; changing a current supplied to thebalancing rotor assembly in response to changing of the angle of pitchto change the lift to maintain a desired angle of pitch.